The Genetically Engineered Mouse Facility (GEMF) generates mouse models for MD Anderson Cancer Center members and offers essential services for archiving important models and receiving novel models from outside sources. The facility provides gene-targeting in mouse embryonic stem cells, blastocyst injection services, pronuclear injection services, embryo and sperm cryopreservation services, rederivation services, in vitro fertilization (IVF), generation of novel mouse embryonic stem cells, and various resources for generating DNA constructs and generating and testing conditional GE mice. In the past 5 years, over 1,200 animal lines were generated by either pronuclear injection or blastocyst injection; over 200 clones were generated by gene-targeting; more than 15,000 embryos were frozen; more than 3,500 straws of sperm were archived, and more than 200 mouse lines were cleaned through rederivation. In addition to knockout mice, the facility has made mouse strains with unique fusions, mutations or protein isoforms to further elucidate genetic effects. Utilization of GEMF services has remained steady at 200-300 procedures per year between 2007 and 2011. The GEMF has seen increases in services such as rederivation, used as more models are brought into the institution, and the mouse archiving services of embryo and sperm cryopreservation. The GEMF has provided services to members of 18 CCSG programs during the last 5 years, serving over 100 Cancer Center members. Peer-reviewed investigators account for 89% of the utilization and 51% of total costs are requested from the CCSG. Publications cited using the GEMF have appeared in Nature, Science, Cell Stem Cell, PNAS and Nat Med. Institutional support for the facility includes over $120,000 in funding for capital equipment since 2007. Future plans include working with the newly established Tai Effector Nucleases facility that can be used to quickly generate targeted animal models. The GEMF is exploring cryopreservation protocols that are more effective at producing high percentage IVF-capable sperm, and the use of IVF to quickly and efficiently produce large numbers of embryos.